Heat-operated alarm



July 16, 1929. v F. A. KUNKLE I HEAT OPERATED ALARM Filed March 5, 1928INVENTOR ATTORNEYS Patented July 16, 19 29.

UNITED STATES FRANCIS A. KUNKLE, or SLATINGTVON, PENNSYLVANIA.

HEAT-OPERATED A RM.

Application filed March 5,

The invention exemplified by this device is an improven'ient intemperature controlled circuit closers adapted for use in alarm systems.Where it is intended. that an alarm 5 shall be given for example by abell, light or similar device, operated by electricity on the attainmentof certain predetermined temperature; it is customary to cause theelectric circuit to be closed by spring operated 10 means released whenthe critical temperature is reached. One of the objects of my inventionis to provide a circuit closer in which the operation is dependent notupon springs but upon the action of gravity alone.

1 Another object of my invention is to pro- ,vi de a circuit closer ofsimple and rugged construction operating when the critical temperatureis reached, by either of two agencies, thus insuring successfuloperation and reduc- 20 ing the risk of the device failing to operate.

A further. object ofmy invention is to pro-' vide fusible elements whichmay be readily replaced. and will also respond more certainly to a risein temperature.

WVith the above and other objects in. View as will hereafterappear, Ihave illustrated in the accompanying drawing one form which my inventionmay take. 7 V

Fig. 1 shows a perspective view and. schematic wirin diagram of thecircuit closer; V

Fig. 2 is a vertical section on the line22 ofFigl;

Fig. 3 is a fragmentary vertical section on the line 22 showing thecontacting weight released and dropped; v

Fig. 4 is a horizontal section on of Fig. 3;

Fig. 5 is a vertical section on the line 55 of Fig. 2 and Fig. 6 is asimilar bars in contact.

The device consist-s generally of a support ing member from which issuspended a series of contact members which may be brought into directcontact either bythe melting or burning or an intervening fusibleelementor the circuit may be closed between these elements by theactionof an electrically conducting weight which is allowedto fallagainst themembers when released from its position by the fusion or combustion of asecond heat responsive element. In the embodiment shown in the drawing,a supporting plate 7 of generally circular shape is made of insulatingmaterial and adapted to be attached to the lower surface of a ceilingbeam or the like. It is the 1.... 4,-4

View with the spring "siliency of themembers.

1928. Serial No. 259,244.

preferred that this base be made of fiber com- 2 position having thedesired insulating qualities. A second plate 8 shown .by preference tobe square in shape is riveted or otherwise attached to the lowersurfaceof the base 7, as indicated at the points 9, 9, thus forming thesupporting member. This plate islikewise of insulating material similarto the base 'i'. In the form shown, the fastenings 9 between the baseand the plate appear at the corners of the latter.

Midway along the side edges of the plate 8 are rivets 10, 10 which passthrough .the plate 8 but not through the base 7 (see Fig. 2). The centerof the plate 8 carries a metal loop 11, the ends of which are spreaddivergently between the plate 8 and base 7 as ,shown in Fig. 2. Thisloop is of sufiicient size to receive a fusible or inflammable elementas will be described later.

The opposite pairs of the four rivets 10 carry the ends 12, 12 of theV-shaped spring bars 13, 1 1, the median portion of each of which'is aflat horizontal extension 15. The ends 12, 12 of the spring'member 13are bent inwardly above the plate 8 and fastened thereto by means of therivets 10, 10. From this construction it is evident that the spring bars13. 14; are disposed atright angles to each other with their medianportions 15, 15 normally in contact under the action of the re- Theportions 15. 15 can be separated out of contact with each otherby'slightly bending the inner spring bar 13.

Electrical contact with. a circuit is provided for each spring bar 13,14by attaching a conductor 16 under the head of one ofthe rivets 10 ofeach opposite pair. 'In thisway each spring bar is" connected to theopposite pole of a source of electricalenergy, for example a battery 17and in series also with signal devices such as the bell 18 and lamp 19..

Alternate means are provided for closing the contact between the springbars 13 and 14.

The median portions 15, 15 of the latter are separated by a channelshaped piece of celluloid 20. Any suitable material may be used in placeof celluloid, it being'merelyimportant that the material be fusible orinflainmable at the critical temperature at which the circuit is desiredto be closed. The piece of celluloid is foldedfrom a iiat sheet ofmaterial and is of sufficient size so that the ends thereof will extendconsiderably beyond the meeting surfaces of the sections 15, 15, withthe side flanges separating the converging portions of the members 18,14. In this way the material will respond to ignition which mightotherwise be retarded by heat conduction away through-metal strips 13,14. p

A weight 21 of conducting metal is suspended by means of an eyelet 22from the loop 11 through a fusible link 23. It is preferred that thefusible link 23 be made of similar material to the member 20 and it isfound that such links may readily be cut and shaped from sheet materialin the same manner as are the members 20.

'In the operation of the device described above, the base 7 is attachedto the structure in the locality where the alarm is to be provided andsuitablecircuit connections 16, 17, 18 and 19 arranged either at thatlocality or in a remote position. The fusible elements 20 and 23 areshaped from appropriate material and assembled with the device. Theelement 20 is inserted between the portions 15, of the spring bars 13,14 and thus maintains these members out of contact.

The weight 21 is suspended from the loop 11 by means of the fusible linkThe de- Vice remains in this position during normal temperatures anduntil a critical temperature is reached. In the latter event the link 23will soften and the weight 21 fall into contact with the spring bars 13,14 as shown in Fig. 3. Thus the electric circuit will be completed fromone side of spring bar 13 to one side of spring bar 14 and the signal 18or 19 brought into operation. The signal will be operated continuouslyuntil the weight 21 is separated from the spring bars 13, 14 by hand.

In the event that a critical temperature is reached without the link 23responding in the manner above indicated, an alternative closing of thecircuit is obtained by the melting or burning of the material of whichmember is composed.

The normal resiliency of the spring bars 4 13 and 14 will thereforebring their median portions 15, 15 into contact resulting in the closingof the electric circuit and the actuation of the alarm.

Again circumstances may exist in which the member 20'is melted or burnedaway, closing the alarm circuit before the link 23 re- I leases theweight and the latter then becomes an alternative of the member 20.

While the above device shows my preferred form of the invention, manychanges may be made in minor details and numerous substitutions ofmaterial accomplished within the scope of the invention as set out inthe following claims.

I claim:

1. In combination with an alarm circuit, a supporting member, a pair ofconverging contact strips held by said member, said strips intersectingat their median portions, suspending means on the supporting memberabove the intersection of said strips, a gravity-operated contactelement and a heat rcsponsive element between the contact element andthe suspending means.

2. In combination with an alarm circuit, a supporting member, a pair ofconverging contact strips held by said member, said strips intersectingat their median portions, suspending means on the supporting memberabove the intersection of said strips, a gravity-operated contactelement, a heat responsive element between the contact element and thesuspending means, and an inflammable element for holding said medianportions of the contact strips out of contact.

3. In 'combintion with an alarm circuit, a supporting member, a pair ofV-shaped contact strips held by said member, said strips intersecting attheir median portions, suspending means on the supporting member abovethe intersection of said strips, a gravity operated contact element, aheat responsive link between the contact element and the suspendingmeans, and circuit connections to each contact strip.

4. In combination with an alarm circuit, a supporting member, a pair ofV-shaped resilient contact strips held by said member, said stripsintersecting at their median portions, and a sheet of inflammablematerial separating said median portions.

5. In combination with an alarm circuit, a supporting member, a pair ofV-shaped resilient contact strips held by said member, said stripsintersecting at their median portions, and a sheet of inflammablematerial separating said median portions, and extendingly outwardlytherefrom.

6. In combination with an alarm circuit, a supporting member, a pair ofV-shaped resilient contact strips held by said member, said stripsintersecting at their median portions, and a sheet of inflammablematerial bent in channel form to separate the converging portions ofthestrips.

7. In combination with an alarm circuit, a supporting member, a pair ofV-shaped resilient contact strips held by said member, said stripsintersecting at their median portions, heat responsive means forbringing said strips into contact, a contact element and a second heatresponsive means for actuating said element to close the circuit throughsaid strips independently of the action of the first said heatresponsive means.

In testimony whereof, I affix my s1 gnature.

"FRANCIS A. KUNKLE.

